Surface treating machine



April 1946- w. s. PEARSON 2,398,556

SURFACE TREATING MACHINE Fild Feb. 28, 1944 4 Shets-Sheet 1 5. Tauszw.

April 16,- 1946. s; PEARSON 5 SURFACE TREATING MACHINE I Filed Feb. 28,1944 4 Sheets-sheaf, 2

William 6.7earson.

AP I 1946- v w. S. PEARSON 2,398,556

SURFACE TREATING MACHINE Filed Feb. 28, 1944 4 SheetsShee-t 3 S ZI iliz'am SJean'son.

April 16, 1946. w. s. PEARSON SURFACE TREATING MACHINE Filed Feb. 28,1944 4 Sheets-Sheet '4 i l i' lf m 5.1%amm Patented Apr. 16, 1946SURFACE TREATING MACHINE William S. Pearson, Severnalark, Md., assignorto Peerco, Inc., Park Ridge, 111., a corporation of Illinois ApplicationFebruary 28, 1944, Serial No. 524,272

14 Claims.

This invention is directed to an improved machine for treating thesurfaces of objects such as by grinding, polishing or buffing the same.

It is an important object of the present invention to provide a machineof the above character which is well adapted for so treating objectswhich have a multiplicity of surfaces, this machine being arranged sothat a plurality of such surfaces may be treated simultaneously.

Itis another object of the present invention to provide an improvedsurface treating. machine havin a plurality of operating elements forsimultaneously treating surfaces of an article requiring differentlength work strokes.

It is still another object of the present invention to provide animproved surface treating machine having a plurality of operatingelements for treating a multiplicity of surfaces requiring differentlength work strokes and having means for interchanging, between theelements, the different strokes so that each element is worn evenly andthus the life thereof is extended.

It is another object of the present invention to provide such a machinehaving a plurality of working elements together with operating meansincluding limit members which delimit the length of the working strokeof each of the tools, the tools being so mounted that they can bequickly manipulated with respect to the delimiting members so that eachtool will assume the working stroke previously passed through byanother. In other words, there is'provided herein an arrange-v ment oflimiting means whereby the stroke length of the tools can beinterchanged for successive operations.

By way of exemplification of my invention, the machine shown herein isadapted for surface treating a forked member such as a cable end havinga pair of parallelly extending, spaced legs, each leg being providedwith a boss through which connection receiving apertures are drilled. Inmanufacturing such a device it is necessary to smooth down the sides ofthe bosses after the drilling operation, this smoothing operation beingperformed heretofore on a milling machine. Preferably the opposite sidesof each of the. prongs are treated together so that working pressuresare in opposite directions. The treatment of the outer surface of one ofthe prongs requires a relatively long stroke of the tool or disk, whilethe treatment of the inner surface can be accomplished only by arelatively short stroke of the tool. In other words, the grinding areaon the'inner and outer surfaces of each of the bosses may be ofdifferent dimension. Thus it will be seen that when the surface treatingdisks operate on one of the bosses, one of the disks will pass through alonger stroke and the other through a shorter stroke. On the other hand,when the device is moved relative to the device so that the disks canoperate on the other boss, the disk which formerly operated through alonger stroke on the outer side of-the first boss must now operatethrough a shorter stroke on the inner side of the second boss. Likewisethe disk which formerly passed through a shorter stroke on the inside ofthefirst boss must now pass through a longer strokeon the outside of thesecond boss. l

Accordingly, it is another important object of the present invention toprovide apparatus of the above character with a plurality of surfacetreating implements, each of which is adapted to be operated through aworking stroke of different length than that through which the otherpasses, therealso being provided means for varying the stroke length ofeach implement so that each may be madeto assume the stroke of the otherduring a successive operation.

It is another important object of the present invention to'provide anapparatus having the above characteristics and yet in which there isprovided for each of the implements a direct driving connection to asource of power.

It is a further object of the invention to pro vide a novel delimitingarrangement whereby the working stroke of each of the disks is changedwith each shaft in the device being worked upon.

Still another object of the'present invention is to provide an improvedsupporting structure for the movable'implements whereby a minimum offorce is required to urge the same through a working stroke" and wherebythe efforts of the operator are thus available almost entirely foraccomplishing the movement of the implements through their workingstroke against the work piece. l

In accordance with the general features'of the present invention thereis provided therein an improved grinding, polishin or buffing machinehaving a stationary base and a work holding assembly, said assemblybeing mounted in laterally shiftable relationship to, the base, directdrive motors and opposed disks therefor and means for rocking oroscillating the disks and motors toward and away from the work and thusover the surfaces to be treated, one of the disks being delimited to ashorter stroke and the other passing through a deeper stroke, saidmachine also including novel delimiting means operable with theshiftable work holding assembly to alternately delimit the workingstroke of first one of the disks and then the other disk upon shiftingthereof with the work holding assembly.

Other objects and advantages of the invention will become apparent fromth following description and accompanying drawings in which:

Figure 1 is'a front view of a machineembodying my invention;

Figure 2 is a top plan view of the machine shown in Figure 1 withcertain parts broken away; Figure 3 is a side view of the machine takenfrom the right-hand side of Figure 2;

Figure 4 is a fragmentary. crossesectionalview taken on the line IVIV ofFigure 2;

Figure 5 is a fragmentary cross-sectional view taken on the line V-V ofFigured Figure 6 is a fragmentary detail viewof the motor mounting anddelimiting device;

Figure 7 is a fragmentary plan View of certain parts of the deviceshowing-the relative positions of the surface treating implements;

Figure 8 is a view similar to Figure"? showing the succeeding positionofthe implements;

Figure'9 is a fragmentary transverse sectional view showing theposition'of certain of the parts delimiting one of the implements to ashort stroke; and

Figure 10 is a view similar to Figure 9 showing the position of theparts when one of theimplements passes through a longer stroke.

It is .to beunderstood that the embodiments shown herein may be variedor modified without departing from the spirit and scopeof the inventionassetforth in the appended claims,

Referring particularly to Figure 1, the device generally consists of abase provided with a superstructure including vertical-standards 2|extendingupwardlyfrom the rear sidethereotthese standards being bridgedat their upper ends by a cross piece 22. y

The base 20 and the upper cross piece or bridge member 22 servestosupport the grinding assembly which includes a pair=of motors 2 3 and 24directly connected-to a pair of grinding disks '25 and 26,-respectively,through drive shafts Z'I-and 28 respectively.

As will be explained presently, the motor 23 and 24, together with theirappurtenances, are rockingly. mounted on the base 20 to be movedforwardly-and rearwardly, independently of one another to perform asurface treating operation. As will also be explained in detailpresentlythere is provided a work Lholding'structure shown generallyat.29 which is laterally, slidabl mounted upon the baseZUand is thusmovable laterally relative to the surface treating assembly tosuecessively expose varying surfaces of the work piece 33 to the surfacetreating operation.

It is'to be understood that the various specific details and thestructural features utilized in the present embodiment of my invention,while highly satisfactory for accomplishing the purposes of my inventionmay be varied, and certain other mechanical expedients may be used whichalso utilize the general principles of my invention.

The base 20 shown herein is essentially box-like in formation and ismade up preferably of four heavy sheet steel plates which providea neat,easily maintained, rigid supporting structure. Referring specificallyto; Figures 3 and 4, it will be seen that there is suitably secured tothe'upper,

'- upper end of the depending part 34.

presently, serves to slidably retain the work holding assembly 29 in theassembly shown.

As will best be seen from Figure 4 the work holding assembly 29 isslidably secured to and maintained upon the base structure 20 by meansof a supporting member 33. This supporting member 33 includes adownwardly depending flange part 34 which overlies the upper part of therear surface of the cross plate 32, there being a shoulder 35 formed inthe member 33 at the This shoulder slidingly abuts against the upperedge of the 'plate32 which serves as a sliding track therefor.

The-member 33is-also provided with an intermediate heavy portion 36 anda generally obliquely disposed, upwardly and outwardly extending portion31.. It will be seen that the outer "surface of the enlarged portion 36is in a plane lying outwardly of the outer surface of the plate member32 and thus a pair of vertically extending braces 38may have theadjacent portion of their inner edges welded to the outer surface of theenlarged portion 35 of the -member 33 as shown at 39 in Figure 4.

These brace or supporting members 38 are pref erably wider at the upperend and tapered rearwardly toward the lower end thereof, whereby thelower ends may be slidingly fitted behind a holder .3 attached to thefront plate 3| of the base 20.

The work holder 29 itself includes a sleeve 4| non-rotatably mounted inan upstanding plate 12 which is secured in turn to a horizontal plate43. Within the collar or sleeve 4| is rotatably and non-slidably mounteda shaft 44 having at its outer end a handwheel 45 and at its inner end 7a plurality of sets of graduated threads 46 which side of the front baseplate 3.1, as by welding or the like, a cross plate 32 which, as will beseen are adapted to be screwed into the threaded end of a fitting to beworked upon and also to be removed from the fitting by rotation of thehandwheel45, The plates 42 and 43 are secured as by welding or theliketoa platesuch as'that shown at '4'! in Figure .4, the plate 41 beingdisposed between the supports or braces 38 and being pivotally securedthereto as by apin 48.

With this constructionit will be seen that the threads 43 together withthe fitting .33 secured thereto may be rocked into an upright positionsuch as shown .by the dotted lines in Figure 4, this rocking movementbeing about the pin 38 and being limited by bolt 41a inplate 41which-engages the edges ofsupports 38. When in this position the fittingmay be exchanged for anotherto be subsequently worked upon. Thereafterthe operator, after he has turned the handwheel idsuificiently to securethe fitting tightly on its respective set of threads 46, may rock theentire assembly on the plate 41 forwardly into the position shown infull lines in Figure 4.

To the end that this forward rocking movement may be delimited to thedesired degree there is provided herein on the oblique portion 31 of themember 33, a pair of opposed stop members each of which includes aportion 49 terminating inwardly in vertically disposed plate sections 50which are each preferably aligned tosupportingly abut one of thebossesSila of the fitting 39 being worked upon.

The portions 43 of thedelimiting members are preferably maintained uponthe oblique portion 31 ofthe supporting member 33 by means.ofsuitablebolts 5i the shanks of whichextend through laterally disposedslots 52 in the member 37. Thus, when the nuts53 of these boltsareloosened, the plate portions 50 may be drawn closer toward oneanother or spread further apart in mounted upon the angle member made upof plates 42 and 43, the shaft member 44 rotatably mounted in the sleeveand carrying the manipulating hand or wheel 45 and threads 46, all ofwhich are mounted upon plates 41; which assembly is in turn pivotallysecured as at 48 between the braces 38, and the upstanding plates 50,the latter being of less thickness than the bosses 30a of the fittingand being aligned therewith.

.For purposes to be described more fully pres-, ently, it is desirable.to first grind the opposedsides of one of the bosses 30a of the fittingand then subsequently to shift the entire work holding mechanism 29 tobring the surfaces of the other boss into alignment with the path of thesurface treating implements and 26. Accord.- ingly, it will be seen thatmovement of the above described assembly laterally will accomplish thispurpose.

Such movement is attained herein by means of an eccentric assembly 54shown best in Figure 1. This assembly includes a disk 55 rotatablymounted at its center as shown at 56 to the plate 32 mounted at theupper end of the front plate 3| of the base 20. This disk is providedwitha crank handle 51 by means of which it maybe rotated as desired.Connected off center of the disk 55 as at 58 is one end of a pitman 59,the other end of which is pivotally secured as at 60 to the outer face36 of the enlarged portion of the member 33 slidably mounted upon theplate 32 as previously described. Preferably a stop bracket 5! is boltedto the outer surface of the plate 32 in such a position that it engagesthe pitman 59 to precisely position the respective bosses a of the toolin readiness for surface treatment in a manner to be describedpresently.

In Figure 1 it will be seen from the misalignment of the center of thehandwheel 45 with the grinding disks 25 and 26 that the left-hand boss30a of the fitting is aligned therebetween. This position is identicalto that shown in Figure 2. After the grinding or finishing operation hasbeen performed on the left-hand boss in a manner to be describedpresently, it will be seen that movement of the handle 51 of theeccentric disk 55 in a counter-clockwise position will shift thesupporting member 33 together with the work holding assembly 29described above, to the left, whereupon the right-hand boss 30a of thetool is brought into alignment to be worked on by the disks 25 and 26.During this movement it will be seen that the pitman 59 has had theright-hand end thereof raised and moved to the left, whereby it hasmoved these parts as indicated 1 To the end that the fitting 30 may beheld tightly in its horizontal position as shown in Figures 2, 3 and 4and so that the fitting will not shift under the influence of the actionof disks 25 V and 26, there is 'provided an arm 62 having a handle 63.This arm is mounted upon a vertical member 64 which is pivotally securedthrough a boss 65 formed in the obliquely disposed portion 31 of-thesupporting member 33. The remote end of the arm 62 is preferably curvedas'shown at 66, this curved portion overlying the upper side of thefitting to hold it tightly down in its horizontal'position and into itsabutting engagement with the respective plates 50 which underlie each ofthe bosses 30a. 1

When the surface treating operation is completedthe operator merelyswings the handle 83 outwardly, whereupon the remote end of the arm62swingsout of its overlying engagement with the fitting to permit themanipulation .of the handwheel 45 and the appurtenant parts, togetherwith a fitting. into the vertical position shown in dotted lines inFigure 4. As indicated previously, the motors 23 and 24, together withtheir respective grinding disks 25 and 26 are mounted in the mechanismso that theymay be swung forwardly and rearwardly tocarrythe respectivedisks "through an oscillatory working stroke against the respectivesurfaces of the bosses 30a of the fitting 30 being worked upon. As willbest-be seen from Figure 3 the side plates 3la of the base 20 are eachprovided with a centrally upstanding portion 61 through which extends arocking rod assembly for the motors. This rocking rod assembly as bestshown in Figure 4 includes a rod 68 which is provided with an operatinglever 10 that is suitably keyed thereto. This rod 68 extends entirelyacross the machine as best shown in Figure l. Rocking movement impartedto the rod 68 by manipulation of the lever 10 is imparted to the motor23 and the respective disk25 by virtue of the mounting arrangement forthat motor and the association thereof with the rod 68.

To this end the motor 23 is mounted upon a generally L-shaped mountingelement 1| having a vertically extending leg portion 12 disposed on theoutside of the base 20"and a substantially horizontal motor receivingportion 13 extending inwardly over the left-hand side of the base asviewed in Figures 1 and 2. The motor 23 is pro-'- videdwith the usualmounting lugs 14 which are secured, by means of bolts 15 to thehorizontal portion 13 of the mounting member H. The mounting member H issupported in the position shown by virtue of the extension 'of theremote end of the rod 68 through the skirt portion I2 thereof as shownbest in Figure l. The rod 68 being enlarged as at 15 to maintain theattached relationship and preferably the rod 68, is keyed to themounting member'll in any suitable manner so as to permit a slightlateral movement of the motor 23 and its mounting member N thereupon. Ifdesired, suitable means may be provided for rockingly supporting theinner portion of the horizontal member 13 such as, for instance, theinner end thereof may be bent downwardly and recessed to receive theupper portion of the rod 68. With such a construction it will be seenthat the parts are entirely open and thus may be easily cleaned andmaintained and at the same time the mounting member H is keyed to therod to be rocked forwardly and rearwardly by movement of the handle IIIwhile the mounting member II together with the motor 23, mayslidelaterally for purposes to be described presently.

The motor 24 is similarly mounted in that it is secured by means ofmounting lugs 11 to a horizontal portion 18 of a'rockable mountingmember 19 having a downwardly depending part similar to that shown at 12in the case of the mounting member "II for the motor23. In order thatthe mounting member 19 together with the motor 24 may be rockedforwardly and rearwardlyindependently oi; heu-inovement'ei the motoriii-and in o d that in. motor 24 withits. m untins member 79 may shif sightl t ally 119011 i s g mechanism. the d pen i g por n 80 of themourtin mernb r 19 is adapted to, ro atebly receive the rod 68. In thisinstance it is to be noted that the mounti g member is n t k ye to therod 68 t may reek iree y t a may shift s g ly laterally there In th s prtion of thea s m ly there is pr vi d ma ipulating handle 82qw'hieh is scur ly ted to t upper ortion of. the d ding section 80 of the mountingmember 19. Thus it will be seen that rocking movement imparted tothelever 82 will directly e fe the mou t ng member 9 and ro the am freelyup n therodfifl, If desired, the inner p rtion ofthe hor zontal section18 of the mounting memb r .19 may e eonst ue edto supeerting y abut aninward; aligned p r otthe edfiii the manner previously des ribed inconiunetion with the h r zonta p rti n 13 f the mounting member 1!. Y

Fr m t e fo e oing it w ll be seen t at t r is provided ein an pparatusin l ding a a 20 upon w ch is moun eda work holdin me h rosin-29. thisWork h ding me anism being eoiprocable'laterally in the apparatusrelative to the-base to dispose various parts of the work successivelyin a pOSitiOnto have thesurfaces thereof oufied, ground 'orpolished.will be seen from Figure- 2, when the eccentric mechanism, 54 is in theposition shown in Figure 1, the left-hand bosstw of efitting 30 isaligned between the grinding disks 25 and 2 6. After the grinding orother surfacing operation has been performed in a manner to be explainedpresently upon the last mentioned lug, it will be seen that the handle51 may be manipulated as previously described, whereupon the other lug30a, is brou ht into oprratin position and disposedbetween the disks 25aud t. Thereafter the operation may be re.- peated upon this second lug.Alsoit will be seen that there is providedherein a stationary b'ase uponwhich the motors together with their respective disks are mounted forrocking forwardly and'rearwardly to perform the surface treatingoperation, this rocking operation being independent in eachof, therespective motors and disks, It will also be "seen that a slight amountof lateralplay-is permitted between the rocking bar 68 and therespective motors, thus permitting an eificient grinding orbutfingoperation in a mannerto be explained presently.

To the end that the motors '23 and 24 may be additionally supported andalso to the end that the motors, togetherwith their respective disks maybe urged resiliently toward one another during the grinding, bufilng orpolishing operation, each is provided with a hanger 83 and 84respectively. These'hangers are arranged to swingingly engage insuitable apertures in opposite ends of the respective motors and areeach provided with ofiset portions 85 and 86 in the bridging portionsthereof respectively, I

-"he' ged in. the fisetstt and 6 are raphl ng elements 8! and 88,respectively which comprise the lower ends of springs 89 and 90respectively. These springs are each provided with bolts 9! and 52respectively at the upper ends thereof which are formed to grapple thecross bar 22 of the super structure of the apparatus. From Figure 1 itwill be seen that the bolts 9| and 92 are secured to the respectivesprings by nuts 93 and 94 which, when rotated, will progress upwardly ordownwardly on he respective bolt tov vary the tension of the respeeti-vespring. The c oss piece 22 of th sup r tr cture s rovided with aplurality'or apertures 95 in the upper side thereof, these aperturesbeing' arranged to receive suitable pins such as those shown at 96 whichserve to retain the upper ends of bolts 92 inwardly of the lower ends ofthe spring. Further adjustment. oi'the tension or the springs andparticularly of the tendency thereof to d aw the motor and therespective dis s .5 and 26 inwardlytoward one anot er and a ai st thework may be accomplished by setting t e pin 96 into holes nearer thecenter of the cross piece 22 or into outwardly disposed holes 95,

ith the foregoi g nstructio it i l b seen that se ral ad anta es arederi d y the s in rra g me t shown he ein.- rst, the s in s tend to uppot he mot r and. thus r e th pe t oi much ii'ert in mo ing th same r ingthe mani ulatio or handl s 1. a d 82 to r ck t e motors and he disk towad a d away r m the wo k, In o her wordst prin s b la ga s he We ght r thm t rs nd. i s- Se ond, the springs, when the mQUOl'S in their rearwardposition and at rest as shown in Figure 3, permit the disks 25 and 26 tospread slightly apart from one another and also tend to urge the diskstoward one another as tension thereon is increased by forward movementof the motors and disks into operative position. The practical advantageof this feature of the spring assembly is that the disks tend to abutthe surfaces of the respective bosses resiliently and thus are springpressed, in eifect, against the surface being worked upon rather thanbeing rigidly mounted so as to cut off, in a single stroke, a certainthickness progressively from the surface being worked upon. This featurehas been found to accomplish the desired results very effectively andyet greatly increase the life of the surface treating implementsparticularly if the implements are grinding wheels as disclosed herein.

It will be seen that in View of the lateral play of the motors and thedisks during the surface grinding operation, and due to the resiliencyimparted to the contact between the disks and the work, some means mustbe provided for delimiting the inward movement of the disks toward oneanother under the influence of the springs so that the depth of thegrinding is delimited to a desired degree, thereby leaving the finishedlug 300. with a predetermined thickness.

To this end each of the downwardly depending portions l2 and of themotor mounting members H and 1'9 is provided with a stop bolt 9'! eachof which is provided with a lock nut 98, whereby it may be securedtightly, in a given, set position. Thus it will be seen that if the nuts98 are loosened and then the bolts 91 are each screwed outwardly aslight distance the springs will be enabled to draw the motor mountingstogether with the motors and the respective disks inwardly to a greaterdegree, thereby to grind a greater depth from the surface of the bosses3011 respectively, whereby these bosses are made thinner by the grindingoperation. Likewise it will be seen that if a lesser depth is to beground from the surface of the bosses or a l ghter polishing pressure isdesired. he bol s 9'! may be screwed further inwardly of the re pectiveparts on which they are mounted. Thus the inward movement of the'motormountings, and the, motors together with their disks unde the influenceof the supporting springs 89 and ,90 is delimited. It will be understoodof coursetllfi t the bolts 91 may be calibrated in any suita le mannerwhe eby predete m ned d s a s between the working faces of the disks maybe obtained quickly and easily. From Figure 1 it will surface treatingpositionsuccessi'vely; for successive grinding, polishing or bufilngoperations. There is also included, a nov'elarrangement for opposedgrinding, buffing, or polishing disks, these disks being movableforwardly and rearwardly, into and out of surface treating positionandyet beingdriven by a direct drive from a respective motor. Thearrangement also includes means for permitting a certain amount or playin the disks and yet resiliently urging the disks toward oneanother apredetermined, regulated amount which is delimited when the desiredthickness of material has been ground from the device being worked uponor when the bufi'ing or polishing pressure ha reached a predeterminedintensity. 1 Another aspect of the present invention is directed toincreasing, the life of the working medium upon the face of the disksand 26. It

; will be understood that if "the width of the surfaces on bosses a asviewed in Figures 7 and 8 I are less than the radialdepth of the surfaceon the respective disk and the disks are moved forwardly into workingcontact with the device being ground only sufficiently far to utilize aperipheral margin of substantially the width of the surface beingground, then the grinding implement will deteriorate over this portionof the surface while the inner part thereof remains intact. Furthermore,as in the present instance, because of the yoked formation of thefitting 30, one of the disks (that grinding the outer surface of therespective boss) may move further forward than the oppositeidisk which isimultaneously grinding the inner surface of that boss.

If this condition prevails for each of the successive grindingoperations, it will be seen that one of, the disks will likewise be wornonly at the outer peripheral part thereof, while the other is "worn moreevenly due" to the further progressive movement thereof over the outerside of the boss.

It is this condition which i availed of in the present invention toincrease the life of both the disk by an alternating arrangement to bedescribed presently. Thi alternating arrangement, 'it is to be noted,permits each of the opposed grinding disks to be subjected alternatelyto. different grinding strokes and thus, while the successive stroke ofeach disk is different, the alternating from one character of stroke tothe other results in an overall operation, whereby each disk isutilizing its entire surface during the grinding cycle and each ispassing through a cycle identical to the other so that one does notwearbefore the other nor does one wear unevenly as to the other.

To the end that the oscillating, working strokes of the disk 25 and 26may be alternated as above described, there is provided herein as bestshown in Figures 7 and 8, a pair of spaced rocking arms 99 and I00.Thesearm are weighted at their outer ends as shown at IOI and I02 andare rockinglysecured on rods I03 and I04 respec:

tively, which extend therethrough. To th en that the arms 99 and I00 maynot shift laterally upon the rods I03 and I04, sets of stop pins I05 andI06 are arranged on each side thereof respectively. The weights IOI andI02 are of uch magnitude that they tend to rock the arms into a positionshown in Figure 4, thereof are elevated.

As best shown in Figure 1 the rods I53 and I04 are welded to thelaterally slidable work supporting assembly 29 as at 'I03a and Wildrespectively.

It will'be noted that the arms 99 and I00 are spaced apart a distanceless than the distance between the forwardlyfinclined edges 3l'b at theupper part of. side panels 3M of thepedestal or support 20. The spacingbetween the arms 99 and I00 is such that when thetwork holding assembly29 is shifted to the right as shown in the drawings, the arm I is inalignment with the right-hand 'side'or panel 3Ia and thus in alignment'withthe stop nut '3Ic protruding from the respective inclined surface3Ib. On the other hand, when the Work holding assembly 29 is shifted tothe left in order that the disks 25 and 26 may operate upon the otherlug of the fitting, the positions of arms 99 and I00 are reversed inthat the arm I00 is drawn out of alignment with the respective stop nut3Ic while the arm 99 is moved into alignment with its respective stopnut 310 at the left of the apparatus By reference to Figures 3, 9 and10, it will be seen that when the arm I00 is aligned with the respectiveside wall or panel 3Ia as shown in Figure 9, it will serve as a. stop orwedge between the respective stop nut 3Id and the respective motormounting base 'I8 t0 limit the forward movement of the respective motorand disk under the influence of manipulation of the handle 10. As willbest be seen in Figures 9 and 10,the

disposition of bolts lfl'lthrough the ends of arms 99 and I00 permits avariation of the limited strokes of the respective disks depending uponthe degree to which the bolts are screwed into or out of the ends of therespective arms. As will be seen in Figure 10, when the arm 99 is in thepositionin Figure 7 the bolt I0'I thereof will not beinterposed betweenthe respective motor base. I3 and the respective inclined surface 3Iband thus manipulation of the lever 82 will enable the disk 25 to berocked forwardly into an extreme position as shown in Figure '7 so thatthe surface treating operation will be accomplished over the radiallyinner portion of the abrading surface thereof. Thus it will be seen thatin the first of two successive operations required to surface both ofthe bosses 30a of the fitting 30, the innerporticn of the disk 25 willbe utilized while the outer portion of disk 26 wil1tbe utilized byvirtue of the interposition of the end of arm I00 between the motor base10 and the upper; forcarried arms 99 and I00 to the left' also, wherebyarm 99 is now brought into alignment with the respective side panel 3Ia,while the arm I00 is moved out of alignment withits respective panel 3Iaso asto be forced into the extreme lower position by oscillation of themotor base I8 siml-f 'lar to the position of arm 99 as shown in Figure10. j'Thus in this instance and as shown by the wherein the inner endson said work holding assembly to move laterally r therewith, andabutment members for engaging said stop members, said abutment membersbeing so spaced that only one thereof is in-alignment with therespective stop member for each lateral position of the work and so thatthe other is in alignment with its respective member when the workholding assembly is shifted laterally for a successive operation uponother surfaces of the work piece, whereby each motor and the respectivesurface treating member thereof passes through alternate limited andlong strokes when rocked into surface treating engagement with the workpiece. a i

3. In a surface treating machine, a supporting assembly including abase, a work holding assembly including means for mounting the samelaterally slidingly on the base and a surface treating assemblyincluding a plurality of motors 'mounted in axial alignment and tomoveforwardly, independently of one another and having surface treatingmembers mounted on the shafts thereof in opposed spaced relationship toreceive a work piece therebetween so that a plurality of opposedsurfaces on said work piece may be treated simultaneously, independent,rock- 'in'gly supported mounting members for each of said motors, a stopassembly for alternately delimiting the rocking movement of saidmounting laterally for a successive operation upon other surfaces of thework piece, whereby each motor and the respective surface treatingmember thereof passes through alternate limited and long strokes whenrocked into surface treating engagement with the work piece, and meansfor urging said surface treating members resiliently toward one anotherand against opposed sides of the work during the surface treatingoperation.

4. In a surface treating machine, a supporting assembly including abase, a work holding assembly including means for mounting the samelaterally slidingly on the base and a surface treating assemblyincluding a plurality of motors mounted in axial alignment and forforward and rearward rocking movement and having surface treatingmembers mounted on the shafts in opposed spaced relationship to receivea work piece therebetween so that a plurality of opposed surfaces onsaid work piece may be treated simultaneously, means for delimiting theforward movement alternately of one and then another of said motorsduring surface treating strokes thereof including a pair of limitmembers arranged to slide laterally with said work holding assembly, oneof said limit members being aligned with each of said motors, said limitmembers being so spaced and arranged that in one position of the workholding assembly one of said limit members serves to delimit the strokeof the respective motor and in another position of the work holdingassembly another limit memberidelimits the stroke of its respectivemotor, said first named limit member then affording full oscillatorymovement of its respective motor.) V

5. In a siufacetreating machine, a work-holding assembly forinaintaining a work piece in a position to be treated; asurface treatingassembly including axially aligned motors each having a surfacetreating; disk member on- ;the shaft thereof, each of said disk membersbeing disposed in facing, spacedopposed relationship, said work holding.assembly" being arranged to maintain a' w'orkpieceso-tlfat-opposedsurfaces thereof are aligned between, said'disks, means for. mountingsaid motors and said: disks for. oscillatory motion toward and away fromsaid work piece, whereby.

alternately,'whereby each disktravels through a shorter and a longerstroke alternately with'each succeeding surface grinding operation. i

' i 6. In a surface treating machine for treating opposed surfaces of anarticle, a pair of axially aligned motors having surface :treating disksdisposed "at-the ends 'of'the shafts-thereof, said disksbeingarrang'edin spaced, facing relationship, meansfor'mountingsaid motorsand saiddisks for forward and rear oscillatory movement, a Work holding(assembly onsaid machine mounted in laterally slidablerelationship'thereto andme'ans for 'movin'g said work holding assemblylaterally to'a'fford disposition of one set of opposed surfacesthereofinregistration with the space between said disks and subsequentdisposition of another set of surfaces thereof in registration with saidspace. 1 7. Iri' asurfacetreatingmachine for treating opposedsurfaces ofan article," a pair of axially aligned motdrs' having surface treatingdisks disposed at theendsof the 'sha'ftsther'eof, said disks beingarranged in spaced, facing relationship, means "for mounting said motorsand said disks for forward and rear oscillatory movement, a workholdingassembly on said machine mounted in laterally slidable relationshipthereto and means for moving said work'holding assembly-laterally toafford disposition of one set of opposed surfaces thereof between saiddisks and subsequent disposition of another set of surfaces thereofbetween said disks, and means for resiliently urging said disks towardone another to afford resilient surface treating abutment thereof withsaid surfaces of the object to be treated and whereby each disk servesas a backing for the surface treating operation of the other.

8. In a surface treating machine, a work holding assembly for securing awork piece in a rigid position while opposed surfaces thereof are beingground or the like, said work holding assembly including a shaft uponwhich said work piece may be rigidly mounted, said shaft being arrangedto be pivoted intoa substantially vertical position to affordapplication and removal of the work piece and being also arranged to bepivoted into a horizontal position whereby a set of opposed surfacesthereof are in position to be work piece, a pair of opposed-surfacetreating disks and a source ofpower directly-connectedto each of saiddisks, each source .of. power. and each disk being mounted forindependent oscilla tory movement toward and awayfromthework piece,means for supporting the work;piec in.- eluding, plate membersdisposed pone side of the forks of said bifurcated-.element, -said plate membersbeing less than theithickhessl of .the forks supported thereby toaiford, oscillation .of the surface treating elements along thesurfacesof said forks without obstructing said surface treating elements.

lOPIn an apparatus, for treating-the, surface of bosses disposed on the.forks ,ofrabifurcated work piece, a pair OfA'OPPQSBdi SUIfZ'OE treatingdisks and a source of power. directly rconnected to each of said diskseachsource of,power'andeach disk being mountedyfor independentoscillatory movement toward and away from-the workpiece, means forsupporting the workpiece including plate members disposedononesideoftheforks of said bifurcated element, said -;plate imernbers being lessthan; the thickness of;. -=the ,forks ,supported thereby toafford-oscillation of the sure face treating ,el'ements aiong thesurfaces of. said forks without obstructing saidlsurface; treatingelements, said plate-like members being mounted for lateral movement toafford supportsfor work:

pieces having forks disposed in varying ,{spaced relationship.

11.. In asurface treating .machine for treating opposed surfacesofan.-article,,a pair of aligned driven shafts, surfacetreatingtoolsdisposed at thereof 11inv registration with; the space between the,toolsand subsequent disposition of another set- :of surfaces thereof inregistration with said space, and means for resiliently urging saidtools axially toward one another to afford resilient surfacetreating-abutment thereof with the set of surfaces of the article to betreated and whereby' ach tool serves asa backing forthe surface treatingoperation of the other tool.

13. In a surface treating machine for treating opposed surfaces of anarticle, a pair of aligned driven shafts, surface treating toolsdisposed at the ends of the shafts, said tools being arranged in spaced,facing relationship, means for mounting said shafts .and said tools foroscillatory movement, into and out of working. position, a work-holdingassembly on said machine mounted to travel substantially parallel tosaid shafts, means for moving said work-holding assembly to afforddisposition, of one set of opposed surfaces thereof in registration withthe space between the tools and subsequent disposition of another set ofsurfaces thereof in registration with saidspace, and means forresiliently counterbalancing said shafts, tools, and mounting meanstofacili-tate the oscillatory movement thereof.

14 .In a surface treating machine, a pair of opposed surface treatingmembers adapted to work on respectively opposite sides of a work piecedisposed therebetween, a driven shaft and shaft supporting means foreach-of said members mounted for independent oscillation transversely ofthe shafts and also relative longitudinal movement thereof with thetreating members, an overhead frame structure, and spring memberssuspended from said framevstructure and con- S. PEARSON.

